We request funds to purchase an integrated system for liquid chromatography coupled with electrospray ionization mass spectrometry (LC-ESI-MS). The system includes a Applied Biosystems (ABI) QStar Elite quadrupole time-of-flight (QqTOF) mass spectrometer capable of rapid scanning and high accuracy mass measurements, and a Waters ultra-high pressure liquid chromatography system for high resolution analyte separations. The proposed instrument will replace a current ABI QStar Pulsar QqTOF mass spectrometer, which must be retired on July 1, 2010, when ABI terminates all repair and service of the current instrument. The system represents a key instrument at the Central Analytical Facility, which serves investigators across the University of Colorado at Boulder (CU-Boulder) campus. The current QqTOF instrument is our workhorse for service samples analyzed by the facility and is currently used by more than 20 laboratories across this campus. It is most heavily used to support research in synthetic organic chemistry and materials development, including structural and elemental analysis of small molecules, natural products, and polymers, and for negative and positive ionization mode analysis of synthetic nucleotides and nucleic acids. It is also used extensively for proteomics applications, including hydrogen-deuterium exchange measurements to map protein-protein and protein-ligand interfaces, and routine ESI-LC-MS/MS to carry out peptide sequencing of protein digests in order to determine subunit compositions of protein complexes. The current QqTOF instrument is used nearly 24/7, and is an essential component of the Central Analytical Facility. Its replacement with the QStar Elite QqTOF is critically needed to continue supporting a wide range of research needs at CU-Boulder. PUBLIC HEALTH RELEVANCE: Funding is requested to purchase a new mass spectrometry system, to replace an existing system that will be retired in 2010, when the manufacturer discontinues repair and service. This is a key analytical technology for "weighing" molecules, which is essential for biomedical research because it allows the chemical composition of molecules to be defined. The instrument will be shared by more than 20 laboratories at the University of Colorado at Boulder, who are synthesizing new materials or characterizing proteins, with the goal of understanding how to diagnose and treat human diseases.